Istg I had to make a whole story for him. I like the idea that William had met Kona before the safe crew had, and that he's still alive and is trying to find a cure. I also like that he kinda got some of his current personality from Willow (like his need for revenge and his survival skills) while still keeping his old naive personality. Also there is a reason behind everything, and he'll likely end up reuniting with Willow again. Though whether or not he'll remember much about her is debatable.